NO339586B1 - External loop power control for wireless communication systems - Google Patents

Description

The present invention is generally related to wireless communication systems. In particular, the present invention is related to power control in such systems.

Wireless telecommunication systems are well known in the art. In order to provide global connectivity for wireless systems, standards have been developed that have been implemented. A current standard in widespread use is known as the Global System for Mobile Telecommunications (GSM). This is considered a so-called second generation mobile radio system standard (2G) and was followed by its revision (2.5G). GPRS and EDGE are examples of 2.5G technologies that offer a relatively high data speed service on top of (2G) GSM networks. Each of these standards seeks to improve upon the previous standard with additional features and enhancements. In January 1998, the European Telecommunications Standards Institute - Special Mobile Group (ETSI SMG) agreed on a radio access plan for third generation radio systems called Universal Mobile Telecommunications System (UMTS). To further improve the UMTS standard, the Third Generation Partnership Project (3GPP) was formed in December 1998. 3GPP continues to work on a common third generation mobile radio standard.

From the European patent application EP 1089456 A2, a solution for managing unnecessary energy increase and call loss during interrupted transmission (DTX mode) of a frame-based transmission system appears.

The international patent application WO 9943105 A1 describes a system and method for transmitting frames of information, the method comprising sending the information continuously throughout the frame when it is in a continuous transmit mode and that the frame is of a first data rate of a plurality of data rates .

A typical UMTS architecture according to current 3GPP specifications is shown in Figure 1. The UMTS network architecture includes a core network (CN) connected to a UMTS terrestrial radio access network (UTRAN) via an interface known as an IU which is defined in detail in current publicly available 3GPP specification documents. UTRAN is configured to provide wireless telecommunication services to users through wireless transceiver units (WTRUs), known as user equipment (UE) in 3GPP, via a radio interface known as Uu. The UTRAN has one or more Radio Network Controllers (RNC) and base stations, known as Node B in 3GPP, which together provide the geographic coverage for wireless communications with the UE. One or more Node Bs are connected to each RNC via an interface known as Iub in 3GPP. The UTRAN can have several groups of node B connected to different RNCs, two are shown in the example shown in Figure 1. Where more than one RNC is arranged in a UTRAN, inter-RNC communication will be carried out via a hidden interface.

Communications externally to the network components are carried out by node B at a user level via the Uu interface and CN at a network level via various CN connections to external systems.

In general, the primary function of the base stations, such as Node B, will be to provide a radio link between the base station network and the WTRU. Typically, a base station will broadcast common channel signals that allow unconnected WTRUs to be synchronized with the base station's time information. In 13GPP, a node B will perform the physical radio connection with the UE. Node B receives signals over the Iub interface from the RNC which controls the radio signals sent from node B over the Uu interface.

A CN is responsible for routing the information to its correct destination. For example, the CN can route voice traffic from a UE that is received by UMTS via one of the Node Bs to a public telephone network (PSTN) or packet data destined for the Internet. 13GPP CN has six main components: 1) a serving General Packet Radio Service (GPRS) supporting node, 2) a gateway GPRS supporting node, 3) a border gateway, 4) a visitor location register, 5) a mobile service switching center and 6) a gateway for mobile service switching center. The serving GPRS supporting node provides access to packet-switched domains, such as the Internet. The port that is the GPRS supporting node is a port node for connections to other networks. All data traffic that goes to other operators' networks or to the Internet goes through the port that is the GPRS supporting node. The border gate acts as a firewall that prevents attacks by intruders from outside the network on subscribers within the network's data area. The visitor location register is a current serving network "copy" of subscriber data needed to provide services. This information is initial from a database that manages mobile subscribers. The mobile service switching center is responsible for line-switched connections from UMTS terminals to the network. The mobile service switching center gateway implements routing functions required at the current location of subscribers. The mobile service switching center gateway also receives and manages connection requests from subscribers from external networks.

The RNC generally controls internal functions of the UTRAN. The RNC also provides intermediate services for communications that have a local component via a Uu interface connection with a node B and an external service component via a connection between the CN and an external system, for example overseas calls made from a mobile phone in a domestic UMTS.

Typically, an RNC will oversee several base stations, manage radio resources within the geographic area of wireless radio service coverage served by the nodes B and control the physical radio resources for the Uu interface. 13GPP will allow the interface in an RNC to provide two connections to the CN: one to a packet-switched domain and the other to a line-switched domain. Other important features of the RNC include confidentiality and integrity protection.

In many wireless communication systems, adaptive transmission power control algorithms are used. In such systems, many communications will be able to share the same radio frequency spectrum. When a specific communication is received, all other communications using the same spectrum will cause interference with that specific communication. As a result, increasing the transmitter power level for one communication will degrade the signal quality for all other communications within that spectrum. However, reducing the transmit power level too low results in undesirable received signal quality, as measured by the signal to interference ratio (SIR) in the receivers.

Various methods of power control for wireless communication systems are well known in the art. Examples of open and closed loop power control transmitter systems for wireless communication systems are illustrated in Figures 2 and 3, respectively. The purpose of such systems is to rapidly vary transmitter power in the presence of a fading propagation channel and time-varying interference to minimize transmitter power while ensuring that data is received at the far end with acceptable quality.

In the communication system such as Third Generation Partnership Project (3GPP) time division duplex (TDD) and frequency division duplex (FDD) systems, several shared and dedicated channels with variable data rate are combined for transmission. Background specification data for such systems is found in 3GPP TS 25.223 v3.3.0, 3GPP TS 25.222 v3.2.0, 3GPP TS 25.224 v3.6 and Volume 3 of the Air Interface Specifications for 3G Multisystem Version 1.0, Revision 1.0 of ARIB (Association of Radio Industries Business) . A rapid method and system for power control adaptation for data rate changes resulting in a more optimal performance is described in International Publication No. WO 02/09311 A2, published on January 31, 2002 and is consistent with US patent application 09/904,001, filed on December 7, 2001, owned by applicant of the present invention.

In 13GPP-CDMA systems, power control is used as the link adaptation method. Dynamic power control is used for dedicated physical channels (DPCH), so that the transmitter power for DPCH is adapted to achieve a quality of service (QoS) with a minimum transmitter power level, which thereby limits the level of interference within the system.

One approach is to split the transmit power control into separate processes, referred to as outer loop power control (OLPC) and inner loop power control (TLPC). The power control system is generally referred to as either open or closed depending on whether the internal loop is open or closed. The outer loops of both types of systems as illustrated in the examples shown in Figures 2 and 3 are closed loops. The inner loop in the open loop type of system illustrated in Figure 2 is an open loop.

In outer loop power control, the power level of a specific transmitter will be based on a target value for SIR. Since a receiver receives the transmissions, the quality of the received signal will be measured. The transmitted information is sent in units of transport blocks (TB), and the received signal quality can be monitored on a block error rate (BLER) basis. The BLER is estimated in the receiver, typically with a cyclic redundancy check (CRC) of the data. The estimated BLER is compared to a targeted quality requirement, such as a targeted BLER, representative of QoS requirements for the different types of data services on the channel. Based on the received, measured signal quality, a targeted SIR adjustment control signal will be sent to the transmitter. The transmitter adjusts the target SIR in response to these adjustment requests.

In third generation partner ship program (3GPP) broadband code-division multiple access (W-CDMA) systems using time-division duplex (TDD) mode, the UTRAN (SRNC-RRC) will set the initially targeted SIR to the WTRU on call/session establishment and then continuously adjust the targeted The SIR of the WTRU during the lifetime of the call as dictated by the observation of the uplink (UL) BLER measurement.

In the inner loop power check, the receiver will compare a measurement of the received signal quality, such as SIR, to a threshold value (ie, the target SIR). If the SIR exceeds the threshold, a transmitter power command (TPC) to decrease the power level will be sent. If the SIR is below the threshold, a TPC to increase the power level will be sent. Typically, the TPC will be multiplexed with data in a dedicated channel to the transmitter. In response to the received TPC, the transmitter will change its transmitter power level. Conventionally, the outer loop power control algorithm in a 3GPP system will set an initial target SIR for each coded composite transport channel (CCTrCH) based on the required target BLER, using a fixed mapping between BLER and SIR, assuming a certain channel condition. A CCTrCH is usually used to send different services on a physical wireless channel by multiplexing several transport channels (TrCH), where each service is on its own TrCH. To monitor the BLER level on a CCTrCH basis, a reference transport channel (RTrCH) may be selected from among transport channels multiplexed on the considered CCTrCH. For example, a TrCH-1 could be selected for RTrCH since it can be considered a midpoint for all channel conditions on CCTrCH, including an AWGN channel. A disparity between a target BLER and a target SIR can vary significantly depending on the given channel condition, especially at very BLER. For example, a target SIR of a target BLER = 0.01 for TrCH-1 in the case 1 channel condition could require more than 4 dB above the target SIR for another transport channel in the AWGN channel condition (ie, TrCH-1 requires a stronger signal) . When the WTRU converts the target BLER to an initial target SIR, there may be an error due to this disparity in channel condition, since the target SIR required for a target BLER varies with channel conditions. As a result, the iterative process for the target SIR determination will have an initial differential that must be compensated upon convergence to the required target, compounded by allowing the CRC process to take place, which overall creates an undesirable delay for the target SIR convergence.

The entire power control algorithm may experience degraded performance as a result of the delay. The delay is expressed in transmission rate units, a transmission time interval (TTI). The narrowest interval is a frame of data, typically defined as 10 ms for a 3GPP communication system. In a 3GPP system, the TTI is 10, 20, 40 or 80 ms long.

A wireless channel can also send a multitude of services, such as video, voice and data, each of which has different QoS requirements. For non-real time (NRT) data service, data is sent in many bursts and of short duration. In a 3GPP system, for example, these data bursts will be depicted as transport blocks on a temporary, dedicated channel (Temp-DCH). This mapping is also referred to expressed as Temp-DCH allocations. One or more transport blocks are depicted on the channel per TTI. Thus, each service will be mapped across several TTIs while the target SIR adjustments are made on a TTI basis during the OLPC for the Temp-DCH allocations.

When voices and broadcast data types are compared, a real-time (RT) voice broadcast is more likely to have a target BLER that is more tolerant (ie, BLER value), but an NRT data broadcast requires a lower rate of error with a lower target DIAPER. Consequently, the expected delays to ensure QoS will be longer for a data download than for a voice transmission. Furthermore, the required transient step size for targeted SIR adjustments will be set depending on the service QoS requirements. While the initially targeted SIR for RT data will always converge to the desired targeted SIR, the initial targeted SIR for NRT data, which is newly assigned per Temp-DCH allocation, not necessarily converging to the desired target SIR due to the short duration of the Temp-DCH allocation.

The present invention understands that Temp-DCH allocation duration can be used as an additional parameter to improve power control. The invention appears from the independent claims 1 and 5.

A method of transmitting power control is provided for a wireless transceiver unit (WTRU) that transmits data signals in a forward channel in selectively sized block allocations wherein the WTRU is configured to make forward channel power adjustments as a function of target metrics calculated based on the data signals received over the forward channel, the method comprising following steps. A series of data signal block allocations, each of a predetermined size S are received at time intervals from the WTRU on the forward channel. For the data signals for each block allocation, target metrics for the WTRU's forward channel power adjustments are calculated based on the detection of predetermined error conditions in the signals received on the forward channel, which includes setting an initial target metric value and storing a final target metric calculated for each block allocation of data. For the data signals in each block allocation after a first block allocation, the initial target metric value is set as a function of the last target metric calculated for an immediately preceding block allocation and an intermediate allocation adjustment based on the time gap from the immediately preceding block allocation. After a preliminary period at the initial value, the target metric will be changed by a size of a step up or a step down at time intervals of a predetermined length whereby the target metric will be increased by the size of the step up if a predetermined error condition has been detected in an immediately preceding time interval or is decreased by the size of the step down if the predetermined error condition has not been detected in the immediately preceding time interval. Setting the step down size at an initial transient state level is based on the predetermined block allocation size S such that the initial step down size is set at a level at least as large as a predetermined step down size for a steady state stable condition level. Where the size of the initial step down is greater than the size of the predetermined step down for the steady state steady state level, the size of the step down is reduced by a selected amount to a lower level if a predetermined error condition has been detected in an immediately preceding time interval until the size of the step down is reduced to the size of the predetermined step down for the steady state steady state level.

A receiving wireless transceiver unit (WTRU) is provided to implement

transmit power control for a transmitting WTRU transmitting data signals in a forward channel in selectively sized block allocations of predetermined size S wherein the transmitting WTRU is configured to make forward channel transmit power adjustments as a function of target metrics calculated by the receiving WTRU. The receiving WTRU includes the following. A receiver receives a series of block allocations of

time-spaced data signals from the WTRU on the forward channel. A processor is configured to calculate targeted metrics to implement forward channel transmit power adjustments in the transmitting WTRU based on detection of predetermined error conditions in the data signals received on the forward channel. The processor is also configured to calculate target metrics so that for the data signals in each block allocation an initial target metric value will be set and a final target metric calculated for each block allocation of data will be stored. The processor is further configured so that for the data signals in each block allocation after a first block allocation, the initial target metric value will be set as a function of the stored last target metric calculated for an immediately preceding block allocation and an interallocation adjustment for time slots from the immediately preceding block allocation . After a preliminary period of an initial value, the target metric will be changed by an amount of one step up or one step down at time intervals of a predetermined length whereby the target

the metric is increased by an amount of the step up if a predetermined error condition has been detected in an immediately preceding time interval or the target metric is decreased by the amount of the step down if the error condition has not been detected in the immediately preceding time interval. The size of the step down is set at an initial transient state level based on the predetermined block allocation size S, so that the size of the initial step down is set at a level at least as large as a size of a predetermined step down for a steady state steady state level, and wherein the magnitude of the initial step down is greater than the magnitude of the predetermined step down for the steady state steady state level.

The size of the step down is reduced by a selected amount to a lower level if a predetermined error condition has been detected in an immediately preceding time interval until the size of the step down is reduced to the size of the predetermined step down for the steady state steady state level. Figure 1 shows an overview of a system architecture in a conventional UMTS network. Figure 2 is a schematic diagram of a conventional open loop power control system for a wireless communication system that implements outer loop power control via a targeted SIR metric. Figure 3 is a schematic diagram of a conventional closed loop power system for a wireless communication system that implements outer loop power control via a targeted SIR metric. Figure 4 illustrates a schematic overmeasure set SIR adjustments according to a hopping algorithm as applied to downlink OLPC. Figure 5 illustrates a plan of targeted SIR adjustments for an example of WTRU downlink OLPC according to the teachings of the present invention. Figure 6 illustrates a plan of targeted SIR adjustments for an example of WTRU downlink OLPC with compressed transient state according to the teachings of the present invention. Figures 7A - 7C illustrate a method flow diagram for an example of downlink OLPC algorithm according to the teachings of the present invention. Figure 8 illustrates a flow diagram for an improved OLPC algorithm for NRT data according to the teachings of the present invention.

The present invention is described with reference to the drawings where like numbers represent like elements throughout. The terms base station, wireless transceiver unit (WTRU) and mobile unit are used in their general sense. The term base station as used herein includes, but is not limited to, a base station, node B, site controller, access point, or other interface device in a wireless environment that provides the WTRU with wireless access to a network with which the base station is associated.

The term WTRU as used herein includes, but is not limited to, user equipment (UE), mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment. WTRU includes personal communication devices such as telephones, videophones and Internet-ready telephones that have network connections. In addition, WTRU includes portable personal computing devices, such as PDAs and notebook computers with wireless modems that have corresponding networking capabilities. WTRUs that are portable can otherwise change locations as referred to as mobile units.

Although the embodiments described in the context of a third generation partner ship program (3GPP) wideband code-division multiple access (W-CDMA) system using time-division duplex mode, the embodiments are applicable in any hybrid code-division multiple access (CDMA)/time-division multiple access (TDMA) ) communication system. In addition, the designs are applicable in CDMA systems, generally such as the proposed frequency division duplex (FDD) mode in 3GPP W-CDMA.

Conventional power control methods for wireless systems such as 3GPP use so-called inner and outer loops. The power control system is referred to as either open or closed depending on whether the inner loop is open or closed. The outer loop in both types of system are closed loops.

Relevant parts of an open loop power control system having a "transmitting" communication station 10 and a "receiving" communication station 30 are shown in Figure 2. Both stations 10, 30 are transceivers. Typically one will be a base station, called a node B in 3GPP, and the other a type of WTRU, called a user equipment UE in 3GPP. For the sake of clarity, only selected components will be illustrated and the invention will be described expressed as a preferred 3GPP system, but the invention has application to wireless communication systems in general, even such systems that perform ad hoc network construction where WTRUs communicate between themselves. Power control is important to maintain quality signaling for multiple users without causing excessive interference.

The transmitter station 10 includes a transmitter 11 having a data line 12 that carries a user data signal for transmission. The user data signal is given a desired power level which is adjusted by applying a transient power adjustment from an output 13 of a processor 15 to adjust the transmitter power level. The user data is sent from an antenna system 14 in the transmitter 11.

A wireless radio signal 20 contains the transmitted data which is received in the receiving station 30 via a receiving antenna system 31. The receiving antenna system will also receive interfering radio signals 21 which affect the quality of the received data. The receiver station 30 includes an interference power measuring device 32 to which the received signal is input, where the device 32 sends out measured interference power data. The receiver station 30 also includes a data quality measuring device 34 to which the received signal is also an input to which the device 34 produces a data quality signal. The data quality measurement device 34 is connected with a processor device 36 which receives the signal quality data and calculates target signal to interference ratio (SIR) data based on a user-defined quality standard parameter received through an input 37.

The receiving station 30 also includes a transmitter 38 which is coupled with the interference power measurement device 32 and the targeted SIR generation processor 36. The receiving station transmitter 38 also includes inputs 40, 41, 42 for user data, a reference signal and reference signal transmitter power data respectively. The receiver station 30 sends its user data and control-related data and reference signal via an associated antenna system 39.

The transmitter station 10 includes a receiver 16 and eta associated receiver antenna system 17. The transmitter station's receiver 16 receives a radio signal sent from the receiver station 30 which includes the receiver station's user data 44 and control signal and data 45 generated by the receiver station 30.

The transmitting station's transmitter processor 15 is associated with the transmitting station's receiver 16 to calculate a transmitter power adjustment. The transmitter 10 also includes a device 18 for measuring received reference signal power with which the device 18 is associated for the path calculation circuit 19.

To calculate the transmitter power adjustment, the processor 15 receives data from a targeted SIR data input 22 that carries the targeted SIR data generated by the receiving station's targeted SIR generating processor 36, an interference power data input 23 that carries the interference data generated by the receiving station's interference power measuring device 32, and a path loss data input 24 that carries a path loss signal which is the output of the path loss calculation circuit 19. The path loss signal is generated by the path loss calculation circuit 19 from data received via a reference signal transmitter power data input 25 which carries reference signal transmitter power data originating from the receiver station 30 and a measured reference signal power input 26 which carries the output of the reference signal power measurement device 18 to the transmitter 11. The reference signal measuring device 18 is connected to the transmitter station's receiver 16 to measure the effect of a reference signal received from the receiver station's transmitter 38. The path loss calculation circuit 19 preferably determines the base path loss rt on the difference between known reference power signal strength passed on by input 25 and the measured received power strength passed on by input 26.

Interference power data, reference signal power data and target SIR values are signaled to

the transmitting station 10 at a rate significantly lower than the time-varying rate of the propagation channel and the interference. The "inner" loop is the part of the system that relies on the measured interface. The system is considered "open loop" since there is no feedback to the algorithm at a rate comparable to the time-varying rate of the propagation channel and the interference that indicates how good the estimates of mini-mal required transmitter power are. If the required transmitter power level changes quickly, the system will not be able to respond according to the change in the power adjustment in a timely manner.

With respect to the outer loop of the open loop power control system of Figure 1, at the remote receiving station 30, the quality of the received signal is evaluated via the measurement device 34. Typical metrics for digital data quality are bit error rate and block error rate. Calculation of these metrics requires data accumulated over periods of time significantly longer than the period of the time-varying propagation channel and interference. For any given metric, there will be a theoretical relationship between the metric and received SIR. When enough data has been accumulated in the remote receiver to evaluate the metric, it is calculated and compared to the desired metric (representing a desired quality of service) in the processor 36 and an updated target SIR is then output. The updated target SIR is the value (in theory) that applied to the transmitter's inner loop would cause the measured metric to converge to the desired value. Finally, the updated target SIR will be passed on, via receiver station transmitter 38 and transmitter station receiver 16, to transmitter 11 for use in the inner loop. The update rate to the target SIR is limited by the time required to accumulate quality statistics and practical limitations on the signaling rate of the power-controlled transmitter.

Referring to Figure 3, a communication system having a transmitter station 50 and a receiver station 70 using a closed loop power control system is illustrated. The transmitter station 50 includes a transmitter 51 having a data line 52 that carries a user data signal for transmission. The user data signal is provided with a desired power level which is adjusted by applying a transmitter power adjustment from an output 53 in a processor 55 to adjust the power level. The user data is sent via an antenna system 54 in the transmitter 51.

A wireless radio signal 60 containing the transmitted data is received in the receiver station 70 via a receiver antenna system 71. The receiver antenna system will also receive interfering radio signals 61 which affect the quality of the received data. The receiver station 70 includes an interference effect measurement device 72 to which the received signal is input, where the device 72 sends out measured SIR data. The receiver station 70 also includes a data quality measuring device 73 to which the received signal is also input where the device 73 produces a data quality signal. The data quality measurement device 73 is connected to a processor 74 which receives signal quality data and calculates target signal to interference ratio (SIR) data based on a user-defined quality standard parameter received through an input 75.

A combiner 76, preferably a subtracter, compares the measured SIR data from the device 72 with the calculated target SIR data from the processor 74, preferably by subtraction, to send out an SIR error signal. The SIR error signal from the combiner 76 is input to the processing circuit 77 which generates step up/down commands based on these.

The receiver station 70 also includes a transmitter 78 which is connected with the processing circuit 77. The receiver station transmitter 78 also includes an input 80 for user data. The receiver station 70 sends its user data and control-related data via an associated antenna system 79.

The transmitter station 50 includes a receiver 56 and an associated receiver antenna system 57. The transmitter station's receiver 56 receives a radio signal sent from the receiver station 70 which includes the receiver station's user data 84 and the control data 85 generated in the receiver station.

The transmitter station's transmitter processor 55 has an input 58 associated with the transmitter station's receiver 16. The processor 55 receives the up/down command signal through input 58 and calculates the transmitter power adjustments based on these.

With respect to the inner loop of the closed-loop power control system, the transmitting station's transmitter 51 sets its power based on high-rate step-up and step-down commands generated in the remote receiving station 70. In the remote receiving station 70, the SIR of the received data will be measured in the measurement device 72 and compared to a target SIR value generated in the processor 74 via a combiner 76. The target SIR is the value (in theory) which, given that the data is received at this value, results in a desired quality of service. If the measured received SIR is less than the target SIR, a step down command will be sent out by the processing circuit 77 via the receiving station's transmitter 78 and the transmitting station's receiver 56, to the transmitter 51, otherwise a step up command will be sent out. The power control system is considered closed-loop since the high-rate feedback in the step-up and step-down commands can respond in real time to the time-varying propagation channel and interference. If required, the transmitter power level will change due to time-varying interference and propagation, which is quickly responded to and adjusts the transmitter power accordingly.

With respect to the outer loop of the closed loop power control system, the quality of the received data will be evaluated in the receiving station 70 by the measurement device 73. Typical metrics for digital data quality are bit error rate and block error rate. Calculation of these metrics requires data accumulated over periods of time significantly longer than the period of the time-varying propagation channel and interference. For any given metric, a theoretical relationship exists between the metric and received SIR. When enough data has been accumulated in the remote receiver to evaluate the metric, it is calculated and compared to the desired metric (representing a desired quality of service) by the processor 74 and an updated target SIR is then output. The updated targeted SIR then becomes the value (in theory) that used in the receiver algorithm, will cause the measured metric and converge to the desired value. The updated target SIR is then used in the inner loop to determine the direction of the step up/down commands sent to the transmitter power scale generation processor 55 to control the power in the transmitter 51.

For outer loop control, regardless of the implementation in either an open loop system as illustrated in Figure 2 or a closed loop system as illustrated in Figure 3, an initially targeted metric, such as targeted SIR, must be set which is recalculated based on the outer loopback that occurs during a wireless communication. Conventionally, the adjustment of the target metric will be performed using a fixed step procedure where set step up and step down increments are used to converge towards a desired target.

This conventional method is modified in the present invention by determining the initially targeted SIR for NRT data. For example, a WTRU in a 3GPP system will at the beginning of a radio link setup or during a handover use the following conditional steps: (1) If the duration (or TTI size S) of the first Temp-DCH allocation is shorter than a threshold (i.e. a predetermined convergence time target) then an initially targeted SIR will be found from an initial mapping in a lookup table and offset by a value (ie 2<*>logio(1/BLER)). The awix value is determined based on the variance of the fading channel conditions. For example, if the fading channel conditions are very uneven, then an awiks value will be adjusted upwards. The downlink outer loop power control does not make any adjustments to the initial target SIR (the target SIR for Temp-DCH is fixed at the initial target SIR). The downlink inner loop controller (ILPC) will run normally to compensate for fast fading and systematic/measurement offset errors. In general, ILPC will not involve targeted SIR adjustments. (2) If the duration of a first Temp-DCH allocation is longer than a threshold (ie the predetermined convergence time target), then an initially targeted SIR will be found from an initial mapping lookup table and the downlink power control operates normally. (3) If the changes in target SIR (actually measured target SIR - initial target SIR from an RNC) for previous services are available, an initial target SIR for a new service will be adjusted as the average of the changes in target SIR instead of above as in the steps (1) and (2). This takes advantage of the increased responsiveness achieved in the outer loop power control for previous services. After the initial target SIR is set, the downlink outer loop power control process will use a "jump" algorithm that adjusts a target SIR based on the result of the CRC for the data. Figure 4 graphically illustrates the use of a generic jump algorithm. Each step up and step down in target SIR is a relatively fixed step size adjustment, once at the beginning of each TTI. A CRC is preferably performed in each TTL and step-down adjustments are made for each CRC that has no errors, while in case of a CRC error detection, a step-up adjustment will be made. In a preferred embodiment of the present invention, the basic jumping algorithm will be represented as follows. If the CRC check in the k-th block does not detect an error, then it will otherwise, if a CRC error occurs, the step down SD and step up SU will be calculated with the following equations:

where SS is the step size for the adjustment for target SIR, which is further discussed below in connection with the preferred step size variation used according to the teachings of the present invention.

There are generally three states for downlink outer loop power control: a preliminary inner loop setting state, a transient state, and a steady state. An example of adjustments to target SIR under the different downlink outer loop power control conditions according to the present invention is illustrated in Figure 5. A method and system for adjusting downlink outer loop power to control target SIR is taught in international application no. PCT/US03/28412, filed September 10, 2003 and which corresponds to US patent application 10/659,673, filed September 10, 2003 and owned by the applicant of the present invention.

As shown in Figure 5, the target SIR is preferably maintained constant throughout the inner loop tuning state. In the inner loop tuning state, the inner loop TPC algorithm will correct the initial system systematic error and random target error without changing the initially targeted SIR.

In the transient state, the outer loop's control algorithm will attempt to correct the initially targeted SIR error caused by the channel's condition inequalities. Initially, the hopping algorithm in the transient state will preferably use a larger step down size to decrease the target SIR quickly, ie it forces a CRC error to occur. In the steady state, the outer loop power control algorithm will attempt to maintain a target SIR by using a relatively small step down size. One aspect of the present invention in this example of WTRU downlink OLPC is the transition of a relatively large step size initially used in the transient state to a smaller step size used in the steady state. Another aspect of this example is to increase the step size in the steady state where there are no CRC errors occurring within a predetermined period.

In the transient state, a large, initial step size SStskunkne will be calculated, for example based on the targeted BLER and a number Nb of transport blocks per TTI for the reference transport channel RTrCH as follows:

For example, where BLERtarget = IO<2>and Nb = 2, then SSts= 2. Thus, through the application of equations 3 and 4 above, the initial step-down and step-up values for the transient state SDT, SUT will be SDT= 0.02 and SUT= (2-1.02) = 1.98.

The presence of CRC errors is used to trigger the reduction in the step size until the transient state size converges to the step size of the steady state SSss- In this example, the steady state SSss would preferably be calculated as follows:

Preferably, when a CRC error occurs during a TTI in the transient state, the step size will preferably be reduced by 1/2. The reduced step size is then applied to the jumping algorithm. The procedure is iterated until the new step size converges to the step size for the steady state. In the example above, convergence will occur after three iterations since SSts= 2<3><*>SSss- Consequently, for each TTI that has a CRC error during the transient state, the next step size will preferably be reduced from the initial step size SSts by l/2<n >, where n is the number of TTIs since the start of the transient state that contained at least one CRC error, until the new step size converges to the step size of the steady state. When convergence occurs, the steady state will begin and no further reduction in step size will take place.

Figure 5 provides a graphic illustration of the above example in practice. In the event of a first CRC error at point A, the targeted SIR will be increased by half of a transient state step up

Sut/2. The CRC error also causes an adjustment in step down size, where subsequent transport blocks received CRC errors result in a decrease in the target SIR by SDT/2. When the next CRC error occurs, the step size up will be reduced to SLV4, the target SIR will be increased by this size, and the step down size will be adjusted to SDT/4. This algorithm continues until the adjusted step up size SUt is equal to the steady state step up size SUs, which in the example shown in both Figures 5 and 6 is equal to SUt/8. At this point the steady state will start. The step up and step down sizes are fixed on SUsogSDs, respectively.

Convergence to the steady state can be quite fast where CRC errors are successively detected when the transient state starts. Figure 6 illustrates this for the example above where several transport blocks are received with CRC errors immediately after the transient state has started, which results in a successive decrease of a transient state step up to the targeted SIR. As shown in Figure 6, the initial CRC result indicates an error at point A, which results in a step up in the targeted SIR by SUt/2, and the setting of the step down size to SDT/2. Figure 6 also illustrates the possibility where the first CRC result after a step up indicates an error. In such a case as shown in point B, the targeted SIR is increased again, but by SUt/4. To continue this worst-case scenario, a CRC error occurs again in the third TTI in the transient state. The next targeted SIR step upward adjustment will then be SUt/8. Since this step-up is equal to the predetermined stable step-up SUs, the transient state ends at this point, and the steady state begins. The target SIR is consistently increased by SUs= SUt/8, and the step down size is set to SDS = SDT/8. In general, any CRC error, regardless of when it occurs, will initiate a step up in the target SIR by an amount that is half the previous step up.

After the steady state has started, the step up and step down sizes will generally be maintained on SU and SDS respectively. Typically where there is little change in the communication metrics, the steady state algorithm will produce a series of successive step up and step down commands in a regular pattern (not shown) as in the case of the conventional jump algorithm. However, where the communication is subject to a rapid change in operating conditions due to changes in interference or other factors, application of the steady state algorithm could be less effective. Consequently, the steady state will be varied from time to time to meet rapidly changing conditions.

During the steady state, when a predetermined observation period has passed without any CRC errors having occurred, the step down size is preferably automatically increased. For example, as illustrated in Figures 5 and 6, after going through eight TTIs without CRC error, the step down size will temporarily be doubled so that the eighth and subsequent step down is twice the SDS size.

It is preferred that the observation period is relatively long since it is assumed that the targeted SIR is close to convergence. Preferably, the observation period is set to 5/BLER following transport blocks. Step down value 2SDS remains fixed until a CRC error occurs, at which time it is returned to SDS. This improves the convergence time when a sudden improvement in channel conditions occurs, which causes an exaggerated measured SIR compared to the desired target SIR. The steady state continues for the lifetime of the CCTrCH communication with this type of adjustment preferably done when there are no CRC errors in a time increment equal to the observation period.

Alternatively, when a predetermined observation period has passed with no CRC errors present, the process can return to the transmitter state to reduce the convergence time, and then proceed to steady state once the target SIR converges as before. In such a case as in the example above, the step down value will be switched from SDS to SDxs as defined above and then be incrementally reduced to the steady state value if a CRC error is detected.

For the case where more than one transport block is received per TTI (ie Nb > 1) for RTrCH within a CCTrCH, the target SIR is preferably adjusted as follows:

where Ne is defined as the number of CRC errors per TTI for RTrCH. However, the step size is preferably only adjusted once per TTI at the beginning of the TTI and only if at least one CRC error is present in the TTI.

The outer loop algorithm described above is preferably implemented in a processor that calculates the target SIR such as processor 36 in the open loop system illustrated in Figure 2 and processor 74 in the closed loop system illustrated in Figure 3. The implementation of the algorithm determines how any CRC error occurs in a new TTI, adjust the step up and step down size correctly, and then perform the step adjustments based on the individual CRC results. For example, consider a TTI with four transport blocks (ie, Nb = 4), where three of the transport blocks contain a CRC error. If the step-up size is SUt/2 and the step-down size is SDT/2 before this TTI, the outer loop algorithm will first adjust the step sizes of SLV4 and SDT/4, and then update the targeted SIR correctly. The end result is that the adjusted target SIR = current target SIR + (SUT/8)

- (SDT/8).

For a 3GPP system, in both the transient and steady state, if the RTrCH is re-selected (ie for variable bitrate services) and the targeted BLER for this new RTrCH is different from the old one, then the SIR step sizes will be recalculated based on the new, targeted BLER. In the steady state, the observation period will also be updated, and the current count of blocks without errors will be reset to 0. In the transient state, in addition to recalculating the step sizes, an additional adjustment will be made to account for the convergence that may already have taken place in this state. In other words, the initial step up SU or step down SD values will not be applied, but rather the current adjustment for the detected CRC error will be applied. As otherwise, the fraction of step up or step down size will be calculated by a factor l/2<n>where n is the number of TTIs since the start of the transient state that contained at least one CRC error. For example, if the current step down size before RTrCH reselection is SDxoid/4, then the step down size immediately after RTrCH reselection must be set to SDxnew/4 and the step up size must be set to SUxnew/4.

In Figures 7A - 7C, a flow diagram is shown for implementing the preferred downlink outer loop power control algorithm in a 3GPP system. In Figure 7A, step 300, preferred procedures during the inner loop tuning state are represented. In step 302, the parameters for inner loop settling time, transient state step size SSts, steady state step size SSss, and TTI count are initialized. The inner loop setting time is preferably set to 100 ms. The value of the transient state step size SSt and steady state step size SSs are initialized according to equations 6 and 7 above respectively. The value for the TTI count is set to zero (0).

In step 304, a comparison is made between the product (TTI count<*>TTI length) and inner loop setting time. If the product is greater than the inner loop's setting time, then the setting state will be finished, and the power control algorithm continues to the transient state. If not, the TTI count will be incremented by one (1) in step 306, and the set rate will return to step 304 for another comparison. Thus, step 300 of the algorithm will ensure that enough TTIs have elapsed to allow the inner loop power control to correct initial systematic error and randomly measured errors.

In Figure 7B, step 307 preferably represents downlink outer loop power control procedures that take place during the transient state. Step 308 is initiated by the affirmative decision in step 304 from the Figure 7A portion of the flowchart. In step 308, the parameters of the transient state will be initialized. The step size is preferably set to SStsi according to equation 5, transient state step down is the step size taken into account in the calculation of the BLER value (i.e. SDT= BLER<*>SSts) and transient state step up SUter the difference between the step size SSt and step down value SDT (i.e. SUt= SSts - SDT).

In step 310, a comparison will be made between the step size SSts and the steady state step size SSss-The initial value of SSts according to Equation 6 as determined in step 302. In step 310, a decision will be made whether the step size SSts is greater than the steady state step size SSss -If not, the transient state will be finished and the algorithm will continue to step 320 in the Figure 7C section of the flowchart. If this is the case, the method will continue to step 312 where it is checked whether Ne number of TTI CRC errors is at least one in number. If not, the method will continue to step 318 where the target SIR is reduced according to the following equation:

In step 318, the target SIR is set to at least a minimum value MINDLSIR. That is, if the target SIR is less than a predetermined value MIN DL SIR, the target SIR is then set equal to this minimum value. When step 318 is complete, the process will return to step 310 with the newly decreased target SIR.

Referring to step 312, if at least one CRC error has been detected for the current TTI, the parameters for step size SSts, step up SU and step down SDT will be adjusted in step 314 in the following manner. The transient state step size SSts is set to half of the current value of SSts-Step up SU and step down SDT values are readjusted according to the new value of the step size SSts for the transient state according to equations 3 and 4.

In step 316, the target SIR will be increased according to the following equation:

The new target SIR value is checked against being greater than a predetermined maximum value MAXDLSIR. If the new target SIR is found to be greater than this maximum value, the new target SIR will be reset to the maximum value MAX DL SIR. The transient state continues by returning to step 310 and repeating the cycle until the transient state step size becomes greater than the steady state step size in step 310 .

In Figure 7C, step 319 preferably represents procedures for the steady state portion of the downlink outer loop power control. In step 320, parameters are adjusted for the steady state including the SIR step size and the steady state step stop value SUs. The SIR step size is set to the steady state step size SSss determined in step 302. The step up value SUs is calculated according to equation 3 using the steady state step size SSss- In step 322 the observation period can be controlled to be greater than or equal to 5/BLER. Initially, the observation period will be less than 5/BLER, in which case step 324 begins where the step down value SDS is equal to BLER<*>SSss-

In step 328, a check is made as to whether at least one CRC error for the TTI has been detected. If this is the case, 330 will begin where the targeted SIR is increased as follows:

The observation period is reset to zero during the detection of a CRC error. If the new target SIR is greater than the value MAX DL SIR, a new target SIR will be set to the maximum value MAX DL SIR. Otherwise, the target SIR will remain at the calculated value as given by Equation 10. The process returns to step 322 to examine the observation period. Once the observation period is greater than or equal to 5/BLER, step 326 will begin where the step down value SDS is doubled. The process then continues to step 328 to check SCR errors. If no CRC error is detected, step 332 begins where the target SIR is reduced according to the following equation:

If the new target SIR value is less than a minimum value MIN DL SIR, the new target SIR is set to the minimum value MIN DL SIR. Otherwise, it remains at the calculated value. Subsequent step 332 returns algorithm state 319 to step 322 and algorithm 319 is then repeated until CCTrCH becomes inactive.

Specifically for NRT data transmissions over TempDCH allocations, the following will summarize preferred processes for Temp DCH allocations followed by the first. The initial target SIR is taken from the last target SIR left by the previous Temp DCH allocation. This initially targeted SIR value is upper bounded by the initially targeted SIR (from the initial imaging lookup table) plus an upper bound margin, and lower bounded by the initially targeted SIR (from the initial imaging lookup table) minus a lower bounded margin. The initially targeted SIR is also adjusted based on the data rate and required BLER for a new Temp DCH allocation.

In the event that the interarrival time of Temp DCH allocation requests is too long (i.e.

10 seconds) then a linear combination of the initially targeted SIR from an RNC lookup table and the limited targeted SIR from the previous Temp DCH allocation with correct weights (i.e. included in the calculation by taking interarrival time into account) will be

used. Once the initial target SIR is fully determined including the above described adjustments for a given Temp DCH allocation, the target SIR value will not be allowed to exceed or fall below this initial target SIR value by a given margin during the outer loop power control operation for this Temp DCH allocation.

In Figure 8, a flow diagram is shown for implementing an algorithm 500 with an improvement of the downlink outer loop power control, particularly for NRT data allocations on Temp DCH using targeted SIR history. The process results in the selection of an initial transient state step size for a hopping algorithm described above, but based on duration of tempDCH allocation. Step 501 preferably provides procedures for producing an adjusted initial target SIR for each Temp DCH allocation.

In step 502, an initial target SIR will be selected using the modified conventional method as described above for the start of radio link setup for a WTRU or in each handover. In step 503, the Temp DCH is checked if it is a first allocation, ie the start of a radio link setup for a WTRU or in each handover. If so, step 504 will initialize a parameter alpha to zero. If not, the algorithm 500 will proceed directly to step 505, where a new initially targeted SIR for this Temp DCH allocation is adjusted with the following equation to compensate for interarrival time between allocations:

where j represents current Temp DCH allocation, target_SIR(j-l) represents the last targeted SIR for the previous Temp DCH allocation, and initialtarget SIR is the initial targeted SIR determined from the image lookup table. The alpha factor is a forgetting factor to take into account the interarrival time between the start of the current Temp DCH allocation and the end of the previous Temp DCH allocation (ie alph = exp(-t\T/10) for T interarrival time).

In step 506, upper and lower limit tests for the calculated, target SIR will be performed according to the values MIN DL SIR and MAX DL SIR. If the value targetSIR is greater than a predetermined maximum value MAX DL SIR, then the target SIR value will be set to this maximum value instead of the calculated value. On the other hand, if the target SIR is less than the predetermined minimum value MIN DL SIR, the target SIR value will be set to this minimum value rather than the calculated value. In step 507, the target SIR will be adjusted based on the data rate.

Further in step 508, the initially transient state step size will be determined based on the duration of the Temp DCH allocation. The RNC sends the Temp DCH allocation duration information encoded on the start block of the NRT data burst, preferably expressed as the number of TTIs. The WTRU receives and decodes the Temp DCH allocation duration accordingly. Step 508 corresponds to step 308 of Figure 7B, but is modified for Temp DCH processing. The following step size choices are described expressed as preferred areas of Temp DCH allocation. If the duration of a Temp DCH allocation is less than 100 TTI (at 90 to 95% in cumulative density function the initial step size will be equal to the steady state step size, (ie SIRstepsizeTS = SirstepsizeS S)).

If the duration of a Temp DCH allocation is between 100 to 200 TTI, then the initial transient step size will be equal to twice the steady state step size (ie SIR step size TS = 2 SIRsteipsizeSS), and outer loop power control will move from transient state to stable state after a CRC error occurrence.

If the duration of a Temp DCH allocation is between 200 and 400 TTI, then SIR step size TS = 4 SIRstepsizeSS, and the outer loop power control will move from transient state to stable state after two CRC error occurrences.

Finally, if the duration of a Temp DCH allocation is greater than 400 TTI, then SIR step size TS = 8 SIR step size SS, which is the same as the initial RT transient step size. The outer loop power control will move from transient state to stable state after three CRC error occurrences where the example described above is implemented.

After step 508, the outer loop power control will initiate the current Temp DCH al location in step 509 according to the enhanced outer loop power control of Figures 7B-7C.

Algorithm 500 repeats with each new Temp DCH allocation.

It should be noted that while the preceding description refers to NRT data as an example, the present invention is applicable to RT also which is of relatively short duration. It is further understood that the parameters including Temp DCH duration, target SIR margins, and interarrival time for Temp DCH allocation requests can be varied to achieve better performance.

Preferably, the components that enhance the algorithms illustrated in Figures 5-8 will be implemented on a simple integrated circuit, such as an application specific integrated circuit (ASIC). However, parts of the algorithms can also easily be implemented in several separate integrated circuits.

The foregoing description makes reference to outer loop power control in the context of a 3GPP system as an example only and is not intended to be limiting. The present invention is applicable to other systems with wireless communication including GSM, 2G, 2.5G or any other type of wireless communication system with the equivalent of outer loop power control implemented.

In a first embodiment for transmitter power control in a wireless transceiver unit (WTRU) transmitting data signals in a forward channel in selectively sized block allocations where the WTRU is configured to make forward channel power adjustments as a function of target metrics calculated based on the data signals received over the forward channel according to the disclosure the method comprising the steps of: receiving data signals from the WTRU in a block allocation having a predetermined size S on the forward channel;

to calculate targeted metrics for WTRU forward channel power adjustments based on the detection of predetermined error conditions in the signals received on the forward channel which include:

to set an initial target metric value, and

after a preliminary period at the initial value, changing the target metric by an amount of a step up or a step down at time intervals of a predetermined length whereby the target metric is increased by the amount of the step up if a predetermined error condition has been detected in an immediately preceding time interval or is decreased by the size of the step down if the predetermined error condition has not been detected in the immediately preceding time interval, and

setting the size of the step down at an initial transient state level based on the predetermined block allocation size S such that the size of the initial step down is set at a level at least as large as the size of a predetermined step down for a steady state steady state level; and where the size of the initial step down is greater than the size of the predetermined step down for the steady state steady state level, reducing the size of the step down by a selected amount to a lower level if a predetermined error condition has been detected in an immediately preceding time interval until the size of the step down is reduced to the size of the predetermined step down for the steady state steady state level.

In a second embodiment, the first embodiment may include that the size of the step up has a defined correspondence with the size of the step down for each level where the calculation of targeted metrics further includes increasing the sizes of the step up and step down by a selected amount if a predetermined error condition has not been detected for a predetermined number of time intervals while the size of the step down is set at the steady state level.

In a third embodiment, the first embodiment may include that the size of the step up has a defined match with the size of the step down for each level, the targeted metrics are targeted signal to interference ratio (SIR) and cyclic redundancy checks are performed to detect the predetermined error condition.

In a fourth embodiment, the third embodiment may include that the step-up magnitudes are significantly larger than respective step-down magnitudes, the initial transient level step-down magnitude being a factor of 2n of the predetermined step-down magnitude for the steady state steady state level, where n is a non-negative integer, and where the size of the step down is reduced, where the reduction is by a factor of 1/2.

In a fifth embodiment, the fourth embodiment may include that the calculation of target metrics further includes increasing the step-up and step-down sizes by a factor of 2 if a predetermined error condition has not been detected for a predetermined number of time intervals while the step-down size is being set at the steady state level.

In a sixth embodiment, the fourth embodiment may include that block allocation sizes S are defined in the increment of transmission time intervals (TTI) and the size of the initial step down is set such that n=0 for S <100 TTi, n=1 for 100 TTI < S < 200 TTI, n=2 for 200 TTI < S < 400 TTI and n=3 for S > 400 TTI.

In a seventh embodiment, the sixth embodiment may include the method being implemented in a universal mobile telecommunications system (UMTS) where the WTRU is a network unit that transmits user signals on a downlink channel and the calculation of targeted metrics is performed in a WTRU that receives the downlink channel and produces power step commands that is sent to the network device on an uplink channel.

In an eighth embodiment, the third embodiment may include that the WTRU is a network unit that transmits user signals on a downlink channel and the calculation of targeted metrics is performed in the WTRU that receives the downlink channel.

In a ninth embodiment, the third embodiment may include that the WTRU transmits user signals on an uplink channel and the calculation of targeted metrics is performed in a network device that receives the uplink channel.

In a tenth embodiment in which open loop transmit power control for the WTRU is implemented, the third embodiment may further include receiving the calculated target SIR in the WTRU on a reverse channel such that the WTRU calculates power adjustments for forward channel transmissions based on the received target SIR.

In an eleventh embodiment, in which closed-loop transmit power control for the WTRU is implemented, the third embodiment may further include producing power step commands as a function of the calculated target SIRs and transmitting power step commands on a reverse channel, and

to receive the power step commands in the WTRU on the reverse channel and to calculate power adjustments for forward channel transmissions based on the received power step commands.

In a twelfth embodiment, a receiving wireless transceiver unit (WTRU) is provided to implement transmit power control for a transmitting WTRU transmitting data signals in a forward channel in selectively sized block allocations wherein the transmitting WTRU is configured to make forward channel transmit power adjustments as a function of target metrics calculated by the receiving WTRU, wherein the receiving WTRU includes: a receiver for receiving data signals in a block allocation having a predetermined size S from a transmitting WTRU on a forward channel,

a processor for calculating target metrics to implement forward channel transmit power adjustments in the transmitting WTRU based on the detection of predetermined error conditions in the data signals received on the forward channel, and

the processor is configured to calculate targeted metrics such that:

after a preliminary period at an initial value, the target metric is changed by a size of a step up or step down at time intervals of a predetermined length whereby the target metric is increased by the size of the step up if a predetermined error condition has been detected in a immediately preceding time interval or the targeted metric is decremented by the size of the step down if the predetermined error condition has not been detected in the immediately preceding time interval,

the size of the step down is set at an initial transient state level based on the predetermined block allocation size S such that the size of the initial step down is set at a level at least equal to the size of a predetermined step down for a steady state steady state level, and

where the size of the initial step down is greater than the size of the predetermined step down for the steady state steady state level, the step down size is reduced by a selected amount to a lower level if a predetermined error condition has been detected in an immediately preceding time interval until the step down size is reduced to the size of the predetermined step down for the steady state steady state level.

In a thirteenth embodiment, the twelfth embodiment may further include that the processor is further configured to calculate targeted metrics such that the step up size has a defined match with the step down size for each level and the step up and step down sizes are increased by a selected amount if a predetermined fault condition has not been detected for a predetermined number of time intervals while the step down size is set at the steady state level.

In a fourteenth embodiment, the twelfth embodiment may further include that the targeted metrics are targeted signal to interference ratio (SIR) where the processor is further configured to calculate targeted metrics such that the step up magnitude has a defined match with the step down magnitude for each level and the the receiving WTRU is configured to perform cyclic redundancy checking to detect the predetermined error condition.

In a fifteenth embodiment, the fourteenth embodiment may further include that the processor is configured to calculate targeted metrics such that the step-up sizes are significantly greater than respective step-down sizes, the initial transient level step-down size being a factor of 2n of the predetermined step-down size for the steady state steady state level, where n is a non-negative integer, and where the step down size is reduced, where the reduction is by a factor of 1/2.

In a sixteenth embodiment, the fifteenth embodiment may further include that the processor is further configured to calculate target metrics such that the step up and step down magnitudes are increased by a factor of 2 if a predetermined error condition has not been detected in a predetermined number of time intervals while the step down size is set at the steady state level.

In a seventeenth embodiment, the fifteenth embodiment may further include that block allocation sizes S are defined by transmission time interval (TTI) increments and the processor is further configured to calculate target metrics such that the initial step down size is set such that n=0 for S < 100 TTI, n=1 for 100 TTI <S <100 TTI, n=2 for 200 TTI < S < 400 TTI and n=3 for S < 400 TTI.

In an eighteenth embodiment, the seventeenth embodiment may further include being implemented for use in a universal mobile telecommunications system (UMTS) wherein the WTRU is a network unit transmitting user signals on a downlink wherein the receiving WTRU is configured to calculate target metrics based on the detection of predetermined error conditions in the data signals received on the downlink channel.

In a nineteenth embodiment, the fourteenth embodiment may further include that the transmitting WTRU is a network device transmitting user signals on a downlink channel wherein the receiving WTRU is configured to calculate targeted metrics based on the detection of predetermined error conditions in the data signals received on the downlink channel.

In a twentieth embodiment, the fourteenth embodiment may further include the transmitting WTRU transmitting user signals on an uplink channel where the receiving WTRU is configured to calculate targeted metrics based on the detection of predetermined error conditions in the data signals received on the uplink channel.

In a twenty-first embodiment in which open loop transmit power control for the transmitting WTRU is implemented, the fourteenth embodiment may further include that the receiving WTRU further includes a transmitter configured to transmit the calculated target SIR on a reverse channel to the transmitting WTRU.

In a twenty-second embodiment in which closed-loop transmit power control for the transmitting WTRU is implemented, the fourteenth embodiment may further include that the receiving WTRU processor is further configured to produce power step commands as a function of the calculated target SIRs and the receiving WTRU further includes a transmitter configured to send power step commands on a reverse channel to the transmitting WTRU.

In a twenty-third embodiment, the embodiment may include transmitting power control for a wireless transceiver unit (WTRU) transmitting data signals in a forward channel in selectively sized block allocations wherein the WTRU is configured to make forward channel power adjustments as a function of target metrics calculated based on the data signals received over the forward channel , wherein the embodiment further comprises the steps of: receiving a series of time-spaced block allocations of data signals from the WTRU on the forward channel;

for the data signals in each block allocation, calculating target metrics for the WTRU's forward channel power adjustments based on the detection of predetermined error conditions in the signals received on the forward channel including setting an initial target metric value and storing a final target metric calculated for each block allocation of data, and for the data signals in each block allocation after a first block allocation, setting the initial target metric value one as a function of the last target metric calculated for an immediately preceding block allocation and an interallocation adjustment based on the time interval from the immediately preceding block allocation.

In a twenty-fourth embodiment, the twenty-third embodiment wherein each block allocation has a predetermined size S wherein the calculated targeted metrics for the WTRU's forward channel power adjustments are based on the detection of predetermined error conditions in the signals received on the forward channel may further include: after a preliminary period at the initial value to change the target metric by a step up or step down size at time intervals of a predetermined length whereby the target metric is increased by the size of the step up if a predetermined error condition has been detected in an immediately preceding time interval or is decreased by the step down size if the predetermined fault condition has not been detected in the immediately preceding time interval,

and

setting the step down size at an initial transient state level based on the predetermined block allocation size S such that the initial step down size is set at a level at least as large as a predetermined step down size for a steady state steady state level and where the initial step down size step down size is greater than the predetermined step down size for the steady state steady state level, to reduce the step down size by a selected amount to a lower level if a predetermined fault condition has not been detected in an immediately preceding time interval until the step down size is reduced to the predetermined step down size for the steady state steady state level.

In a twenty-fifth embodiment, the twenty-third embodiment may include that the interallocation adjustment is determined by (alpha<*>previous_target_SIR)+((l-alpha)<*>initial_target_SIR)), where alpha is a forgetting factor to compensate for longer than expected interallocation time , previoustargetSIR is the targeted metric from the previous block allocation, and initialtargetSIR is the first targeted metric.

In a twenty-sixth embodiment, the twenty-third embodiment may include including an upper and lower bound test to set the initially targeted metric, wherein the upper bound is a first predetermined value added to the initial value and the lower bound is a second predetermined value subtracted from it initial value.

In a twenty-seventh embodiment, the twenty-third embodiment may include including an adjustment to the target metric based on data rate.

In a twenty-eighth embodiment, the twenty-third embodiment may include that the step up size has a defined match with the step down size for each level, the targeted metrics are targeted signal to interference ratio (SIR) and cyclic redundancy check is performed to detect the predetermined error condition.

In a twenty-ninth embodiment, the twenty-eighth embodiment may include that the step-up magnitudes are significantly larger than respective step-down magnitudes, the initial transient level step-down magnitude being a factor of 2n of the predetermined step-down magnitude for the steady state steady state level, where n is a non-negative integer, and where step down the size is reduced, where the reduction is by a factor of 1/2.

In a thirtieth embodiment, the twenty-ninth embodiment may include that the calculation of target metrics further includes increasing the step-up and step-down sizes by a factor of 2 if a predetermined error condition has not been detected for a predetermined number of time intervals while the step-down size is set to the steady state level.

In a thirty-first embodiment, the twenty-ninth embodiment may include that block allocation sizes S are defined in increments of transmission intervals (TTI) and the initial step down size is set such that n=0 for S < 100 TTI, n=1 for 100 TTI < S < 200 TTI, n=2 for 200 TTI < S < 400 TTI and n=3 for S > 400 TTI.

In a thirty-second embodiment, the thirty-first embodiment may include that the method is implemented in a universal mobile telecommunications system (UMTS) where the WTRU is a network unit that transmits user signals on a downlink channel and the calculation of targeted metrics is performed in a WTRU that receives the downlink channel and produces power step commands that are sent to the network device on an uplink channel.

In a thirty-third embodiment, the twenty-eighth embodiment may include that the WTRU is a network unit that transmits user signals on a downlink channel and the calculation of targeted metrics is performed in a WTRU that receives the downlink channel.

In a thirty-fourth embodiment, the twenty-eighth embodiment may include that the WTRU transmits user signals on an uplink channel and the calculation of targeted metrics is performed in a network device that receives the uplink channel.

In a thirty-fifth embodiment in which open loop transmit power control for the WTRU is implemented, the twenty-eighth embodiment may further include receiving the calculated target SIRs in the WTRU on a reverse channel such that the WTRU calculates power adjustments for forward channel transmissions based on received target SIRs.

In a thirty-sixth embodiment, the embodiment may include a receiving wireless transceiver unit (WTRU) for implementing transmit power control for a transmitting WTRU transmitting data signals in a forward channel in selectively sized block allocations wherein the transmitting WTRU is configured to make forward channel transmit power adjustments as a function of target metrics calculated in the receiving The WTRU comprising: a receiver for receiving a series of block allocations of space-timed data signals from the WTRU on the forward channel;

a processor for calculating target metrics to implement forward channel transmission power adjustments in the transmitting WTRU based on the detection of predetermined error conditions in the data signals received on the forward channel, and

the processor is configured to calculate targeted metrics such that:

for the data signals for each block allocation, an initial target metric value is set and a final target metric calculated for each block allocation for data is stored, and for the data signals in each block allocation after a first block allocation, the initial target metric value is set as a function of the last stored target metric calculated for an immediately preceding block allocation and the time interval from the immediately preceding block allocation.

In a thirty-seventh embodiment, the thirty-sixth embodiment may further include each block allocation having a predetermined size S wherein the processor is further configured to calculate target metrics such that: after a preliminary period of an initial value, the target metric is changed by a step up or step down magnitude at time intervals of a predetermined length whereby the targeted metric is increased by the step up magnitude if a predetermined error condition has been detected in an immediately preceding time interval or the targeted metric is decreased by a step down magnitude if the predetermined error condition has not been detected in the immediately preceding time interval, the step down size is set at an initial transient state level based on the predetermined block allocation size S, such that the initial step down size is set at a level at least as large as a predetermined step down larger lse for a steady state steady state level, and

where the initial step down size is greater than the predetermined step down size for the steady state steady state level, the step down size is reduced by a selected amount to a lower level if a predetermined error condition has not been detected in an immediately preceding time interval completely until the step down size is reduced to the predetermined step down size for the steady state steady state level.

In a thirty-eighth embodiment, the thirty-sixth embodiment may further include that the interallocation adjustment is determined by

(alph<*>previous_target_SIR)+((i-alpha)<*>initial_target_SIR)), where alpha is a forgetting factor to compensate for longer than expected interallocation time, previoustargetSIR is the target metric from the previous block allocation, and initialtargetSIR is the first targeted the metric.

In a thirty-ninth embodiment, the thirty-sixth embodiment may further include that the processor is further configured to perform an upper and lower bound test to set the initially targeted metric wherein the upper bound is a first predetermined value added to the initial value and the lower bound is a second predetermined value subtracted from the initial value.

In a fortieth embodiment, the thirty-sixth embodiment may further include the processor being further configured to adjust target metrics based on data rate.

In a forty-first embodiment, in which the targeted metric is a targeted signal to interference ratio (SIR), the thirty-sixth embodiment may further include that the processor is further configured to calculate targeted metrics such that the step up size has a defined match with the step down size for each level and the receiving WTRU is configured to perform cyclic redundancy checking to detect the predetermined error condition.

In a forty-second embodiment, the forty-first embodiment may further include that the processor is configured to calculate target metrics such that the step-up sizes are significantly greater than respective step-down sizes, the initial transient level step-down size being a factor of 2n of the predetermined step-down size for the steady state steady state level, where n is a non-negative integer and where the step down size is reduced, where the reduction is by a factor of 1/2.

In a forty-third embodiment, the forty-second embodiment may further include that the processor is further configured to calculate target metrics such that the step up and step down magnitudes are increased by a factor of 2 if a predetermined error condition has not been detected in a predetermined number of time interval, while the step down size is set at the steady state level.

In a forty-fourth embodiment, the forty-second embodiment may further include that block allocation sizes S are defined as transmit time interval (TTI) increments and the processor is further configured to calculate target metrics such that the initial step down size is set such that n=0 for S < 100 TTI, n=1 for 100 TTI < S < 200 TTI, n=2 for 200 TTI < S < 400 TTI and n=3 for S > 400 TTI.

In a forty-fifth embodiment implemented for use in a universal mobile telecommunications system (UMTS) where the WTRU is a network unit that transmits user signals on the downlink, the forty-fourth embodiment may further include that the receiving WTRU is configured to calculate target metrics based on the detection of predetermined error conditions in the data signals received on the downlink channel.

In a forty-sixth embodiment, the forty-first embodiment may further include that the transmitting WTRU is a network unit that transmits user signals on a downlink channel where the receiving WTRU is configured to calculate targeted metrics based on the detection of predetermined error conditions in the data signals received on the downlink channel.

In a forty-seventh embodiment, the forty-first embodiment may further include the transmitting WTRU transmitting user signals on an uplink channel where the receiving WTRU is configured to calculate targeted metrics based on the detection of predetermined error conditions in the data signals received on the uplink channel.

In a forty-sixth embodiment in which open loop transmit power control for the transmitting WTRU is implemented, the forty-first embodiment may further include that the receiving WTRU further includes a transmitter configured to transmit calculated target SIRs on a reverse channel of the transmitting WTRU.

In a forty-seventh embodiment in which closed-loop transmit power control for the transmitting WTRU is implemented, the forty-first embodiment may further include that the receiving WTRU processor is further configured to produce power step commands as a function of the calculated target SIRs and the receiving WTRU further includes a transmitter configured to sending the power step commands on a reverse channel to the transmitting WTRU.

Claims (8)

1. Wireless Transmit/Receive Unit, WTRU, comprising: a processor configured to operate in a first transmission mode and a second transmission mode, wherein in the first transmission mode, a dedicated uplink channel transmission is continuous and in the second transmission mode, a dedicated uplink channel transmission non-continuous, the processor configured to determine whether to transmit the dedicated uplink channel transmission in the first transmission mode or the second transmission mode, a transmitter configured to transmit the dedicated uplink channel transmission in the determined transmission mode to a base station; and a receiver configured to receive power commands from the base station in response to the dedicated uplink channel transmission; and the processor is configured to add a signal to interference ratio, SIR, value to an SIR measure for use in determining a transmitter power command in at least one condition that the processor is operating in the second transmission mode. 2. WTRU according to claim 1, wherein a value of the received power commands is based on an adjusted signal to interference ratio, SIR. 3. WTRU according to claim 1, wherein a value of the received power commands is based on the transmission mode. 4. The WTRU of claim 2, wherein the adjusted SIR is based on the transmission mode. 5. Method for implementing a wireless transmit/receive unit, WTRU, comprising: operating, with a processor in the WTRU, in a first transmission mode and a second transmission mode, wherein in the first transmission mode, a dedicated uplink channel transmission is continuous and in the second transmission mode is a dedicated uplink channel transmission non-continuously, determining, with a processor in the WTRU, whether to transmit the dedicated uplink channel transmission in the first transmission mode or second transmission mode, transmitting, with a transmitter in the WTRU, the dedicated uplink channel transmission in the determined the transmission mode of a base station; and receiving, with a receiver in the WTRU, power commands from the base station in response to the dedicated uplink channel transmission; and adding, by the processor in the WTRU, a signal to interference ratio, SIR, value to an SIR measure for use in determining a transmitter power command in at least one condition that the processor is operating in the second transmission mode. 6. The method according to claim 5, in which a value for the received power commands is based on an adjusted signal to interference ratio, SIR. 7. Method according to claim 5, in which a value of the received power commands is based on the transmission mode. 8. The method of claim 6, wherein the adjusted SIR is based on the transmission mode.